Carter, who left the party in December, is joined by Joel Levy – previously director of strategy at Philip Gould Associates – as head of strategy and research. Lord Gould, renowned for being Tony Blair's polling guru, will also advise the London office in an independent capacity.

Carter said PSB's business was 'to take lessons from the campaign trail and apply them to the boardroom'.

PSB London is based at the offices of sister firm Burson-Marsteller. Mark Penn, who co-founded the company 30 years ago with its CEO Mile Berland, became B-M's New York-based global CEO at the end of last year.

Penn claimed that PSB used a 'unique approach to messaging and competitive research to help political leaders and corporate clients better understand and connect with their customers'.

He added that the London office would 'use that understanding to help companies win their battles in the competitive European market'.

Penn was the lead political strategist for US president Bill Clinton in 1996.

Carter said the London operation was launching with six staff but aimed to expand significantly this year. BP and Vodafone are among the firm's UK clients. WPP acquired PSB in 2001.

Carter worked for Labour for eight years and was previously a lecturer on politics at York University.